Lands



PIETER DE LA NGE AND ROBERT AERNOUT BARON VAN LYNDEN. HEATING c'omnucronFOR THERMIC TELEPHONES. IAPPLFCATION FILED NOV. 4,.195.

Patented Nov. 18, 1919.

- Pieterdella e ud .Fobez-ilferlwzztjaron v'dnmden orzey UNITED STATESPATENT. OFFICE.

PIETER DE LANG-E AND ROBERT AERN OUT BARON VAN LYNDEN, OF UTBECHT',NETHER- LANDS, ASSIGNORS, IBY MESNE ASSIGNMENTS, TO AMERICANT'I-IERMOPHON E COM- PANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OFMASSACHUSETTS.

HEATING-CONDUCTOR FOR THERMIG TELEPHONES.

Specification of Letters Patent.

, Patented Nov. 18, 1919..

Application filed November 4, 1915. Serial No. 59,623.

To all whom it may concern:

Be it known that we, Prnrnn on Lance, and ROBERT AERNOUT BARON VANLYNDEN, both subjects of the Queen of the Netherlands, and residing atUtrecht, in the Neth erlands, have invented new and useful Improvementsin I-Ieating-Conductors for Thermio Telephones, of which the followingis a specification.

ur invention relates to heating conductors for thermic telephones, andhas for its object to provide a heating conductor which owing to itsnovel structure afi'ords the greatest possible sound producing lengthwithin a comparatively small space.

Heating conductors according to our invention are illustrated by way ofexample in the accompanying drawings, in which Figure 1 shows, inelevation, one form of heating conductor according to our invention,while Fig. 2 similarly illustrates a modification.

Referring to Fig. 1 the illustrated heating conductor consists of aWollaston wire 2 having round or flattened legs 1 and an intermediateportion formed into a complete loop 3.

Instead of one complete loop, the heating conductor may have tWo or moresuch loops. Fig. 2 illustrates heating conductor l with two completeloops 5 and 6. As'in Fig. 1, the ends of the wire are provided withlaterally-bent legs 7, which, as in Fig. 1, may be round or flat incross section.

By a complete loop we mean one in which the bend extends through anangle of at least 360, so that when viewed as shown in the drawings,portions of the wire will ap pear to cross each other.

Forming the wire with a complete loop or a plurality of such loops hasthe advantages that its sound emitting length is as great as possiblewhile the wire does not require more space than the ordinary, areshapedwires. It will be understood that said complete loops form part of thesound emitting portions or sound portions of the wires. The VVollastonwire formed as described is dipped in a bath of acid with itsloop-shaped part hanging down, and exposed to the ac tion of the acidfor the desired length. Instead of preparing the wire by the Wollastonprocess, an exceedingly fine Wire, the heating conductor, as requiredfor the purpose specified, may also be obtained by drawing or spinningthe wire from liquid metal.

We claim:

1. A heating conductor for thermic telcphones, provided with a loop andwith alining ends integral with said loop and bent laterally in oppositedirections.

2. A heating conductor for thermie telephones, provided with a centrallooped or coiled sound portion of more than 360 and laterally-bent endsintegral with said looped portion.

In testimony whereof, we have signed this specification.

PIETER DE LANGE. ROBERT AERNOUT BARON VAN LYNDEN.

